1. Field of the Invention
This invention pertains to methods and apparatus for forming a core of belts, plies and beads for positioning in a spin casting mold to receive a flow of an elastomeric material passed therein, to form a transport tire.
2. Prior Art
The present invention is in a new and unique automated method or process and apparatus for the rapid formation of a core of belts, plies and beads, requiring minimum of manual operations and the positioning of the cord in a spin casting mold to form an elastomeric tire. The belts and plies are pre-formed by weaving methods as open sleeves for individual fitting onto a mandrel portion of an inner mold that receives an outer mold fitted thereover. The core is formed in layers with spacers or separators between the mold, plies and belt or belts and, after formation on the inner mold, the core is maintained in the assembled mold annular space to be encapsulation in a tire that is formed from an elastomeric material, preferably in a spin casting process.
The core of the invention is formed in steps, including first positioning a separator formed from a porous material, such as cotton batting, over a mandrel portion of the inner mold. Then successive layers of a separator, plies, a separator, a belt, a separator and a final tire cord layer, are fitted around the crown of the inner mold, sandwiching over one another, with the plies and belt or belts preferably arranged as woven sleeves that are fitted over the crown and with beads fitted to the core sides and receive the plies cords ends folded therearound. Whereafter, the inner mold is coupled to an outer mold, providing a finished mold that contains the core that is to receive a flow of an elastomeric material. Which elastomeric material flow passes through the separators or spacers, and the respective plies and belt or belts, melding with the fibers of cords of the plies and belt or belts, providing an optimum spacing distance apart of the plies, beads and belt or belts in a finished tire. The elastomeric material flow consists of component chemicals that are combined and react, providing an exothermic reaction generating heat, in forming a finished tire. Where, heretofore in earlier tire forming processes, workers have sequentially positioned, and bonded together with adhesives, layers of green rubber and fabric and steel belting around a mandrel, building a tire from the inside out. Which process includes encapsulating beads in the side walls ends, with the assembly then cooked or vulcanized, under heat and pressure, in a mold, forming a tire. Additionally, while some prior art exists showing a attempts at molding tires utilizing elastomeric compounds other than rubber, such have not provided, as does the invention, for building a tire core of plies, belts and beads utilizing separate pre-formed sleeve or tubular sections of plies and belts that are formed by weaving methods from rayon or cotton cord and provide for sequentially pulling success spacer, plies and belts layers over a tire a mandrel, forming the core as a stack of separators or spacers, plies and belts, with the plies cord ends folded around the beads, that then receive a tire cord wound around the core outer circumference, completing the core.
Examples of such earlier patents that do not involve the above steps and the apparatus for their practice of the invention are set out in U.S. Patents to Maynard, U.S. Pat. No. 2,476,884; to Cadwell et al., U.S. Pat. No. 2,873,790 and to Cesar, et al., U.S. Pat. No. 4,476,908: and in a British Patent to Merriman, et al., U.S. Pat. No. 1,246,471. Prior to the present method one of the present inventors was an inventor of a U.S. Patent Application for a Tire Core Package for Use in manufacturing a “Tire with Belts, plies and Beads and Process of Tire Manufacture” Ser. No. 10/143,678, filed May 13, 2002, that is presently pending, and sets out a process, utilizing a sandwich of pre-cured elastomer between layers of plies and belts formed over a mandrel for fitting into a mold, for forming a tire utilizing a spin casting method. Also, one of the inventors of the present application is the sole inventor of a U.S. Patent Application for an “Elastomeric Tire With Arch Shaped Shoulders” filed May 28, 2004, assigned Ser. No. 10/856,652. Further, the present invention is a further development of the invention as shown and discussed in a recently filed U.S. Patent Application of the inventors, entitled, “Method and Apparatus for Forming a Core of Plies, Belts and Beads and For Positioning the Core in a Mold For Forming an Elastomeric Tire and the Formed Elastomeric Tire”, filed Jun. 4, 2004, Assigned Ser. No. 10/860,997.
Unique to the invention is a separate formation of flexible cylindrical plies and belt sleeves that are each a weave of plie and belt cords, with the sleeves preferably each including strands of an elastic material woven into the sleeve that allow the sleeve to expand when it is pulled across a frustrum cone from the lesser to greater diameter cone ends, and contract, fitting snugly to, the mandrel crown. Which cone or cones for use with the invention may be different cones that vary in successively larger greater diameter ends depending upon which sleeve or plies or belt or belts is being pulled thereover, or may be the same cone with the sleeves having a capability to expand sufficiently to be pulled thereover and contract into tight fitting engagement over the mandrel crown. In practice, the cone greater diameter end is aligned with the edge of a mandrel that is the shape of a tire inner surface having a separator layer fitted thereover, with the separator covered mandrel crown to receive, successively, sleeves or plies, belt or belts fitted thereon, with spacers or separators fitted therebetween. With, in practice, the sleeves of plies, a belt or belts being slid off the cone and pass onto the mandrel crown where they individually retract into tight fitting engagement, forming a stack of separators or spacers, plies and belt or belts Which core stack is then capped with a wrap of tire cord. With the plies ends draped down the mandrel sides to receive a bead fitted to each core side that the plies ends are folded around.
A practice of the method on the apparatus of the invention provides for a near automated system for forming a core of plies, beads and belts that is encapsulated in a tire formed by a spin casting method, and is a major improvement to tire formation as a first efficient method for the manufacture of a balanced transport tire from an elastomer, notably urethane.